Japanese business-day calculator: check if a date is a business day, add N business days to a date, or count business days in a range. Accounts for weekends and Japanese national holidays; optional Saturday and year-end/new-year rules.

Japanese national holidays for a given year (1955-2027), from the official Cabinet Office dataset.

Verify a Japan qualified-invoice-issuer registration number (インボイス登録番号, "T" + 13 digits) against the National Tax Agency publication dataset. Returns registration status (active/cancelled/not found), registration date, and — for corporations — the registered name and corporate number. Includes corporate-number checksum validation. Essential for AP automation and expense agents processing Japanese invoices/receipts.

Resolve a Japanese company to its official registry record: 13-digit corporate number (法人番号), canonical registered name, head-office address, entity type, and active/closed status. Query by name (fuzzy normalization: legal-form words, zenkaku/hankaku and kana variants are handled) or by corporate number. Source: National Tax Agency corporate number registry, all ~5M registered corporations in Japan.